Question

Which of the following is the step of TCA cycle showing substrate levelphosphorylation?

• A. Succinyl CoA$\to$ fumarate
• B. Succinyl CoA $\to$ succinate
• C. Fumarate$\to$Malate
• D. Malate$\to$oxaloacetate

Answer 1

The correct option is B Succinyl CoA $\to$ succinate

option $"B"$ is correct.

Succinyl COA $\to$ succinate is the step of TCA cycle showing substrate level phosphorylation. The cleavage of the thioester bond of succinyl COA is coupled with the phosphorylation of an ADP or a GDP (substrate level phosphorylation). This is catalyzed by succinyl COA synthetase. ATP and GTP are energetically equivalent.